Interactions between PVC geomembranes and compacted clays

The interactions between plastic soils and polyvinyl chloride (PVC) geomemb ranes were studied using a direct shear device under as-compacted condition s. The PVC geomembranes had smooth or textured surfaces, and the soils were of plasticity index (PI) ranging from 35 to 100%. The peak and residual fa ilure envelopes were expressed using Coulomb failure criteria. The adhesion and angle of friction increased for Pls up to 70% and subsequently recorde d a decrease. The adhesion is larger for the peak strength compared to the residual strength, but it was the reverse for the angle of friction. The ef ficiency in terms of adhesion appeared more relevant than that of the angle of friction in expressing the interactions between geomembrane and cohesiv e soils, The smooth and textured geomembranes showed little difference in r esults at the residual state.